Switching selector for printing telegraph systems



Apr 1942- R. v. MORGENSTERN EIAL. 2,279,335

SWITCHING SELECTOR FOR ERINTING TELEGRAPH SYSTEMS 'Filed Aug. 3, 1940 LINE |o Li I REPERE CONTACTS ACTUATED wH|| E OTHER CONTACTS ARE CLOSED ATTcSRNEY' and Patented Apr. 14, 1942 UNITED STATE SWITCHING SELECTOR FOR. PRINTING TELEGRAPH SYSTEMS Ronald V. Morgenstern, Irvington, and Henry P. Gilbert, Hackensack, N. J assignors to The Western Union Telegraph Company, New York, N. Y., a corporation of New York Application August 3, 1940, Serial No.'350,824

6 Claims. (Cl. 17823) This invention relates to printing telegraph systems and mor particularly to arrangements for selecting printing telegraph stations or lines in response to the transmission of code combinations of impulses to a printer.

In accordance with the invention a switching system is provided which operates in response to the transmission of characters or code combinations of impulses normally used in the transmission of messages. Thus, for example, a plurality of characters or selected code combinations may be employed to eiiect'a switching function when they occur with a definite time relation which does not normally take place in the regular transmission of messages, or a plurality of characters or selected code combinations may? be transmitted in succession to efiect the switching operation where such'code combinations are not normally transmitted in that particular order.

One object of the present invention, therefore, is to provide a simplified switching selector controlled by the reception of predetermined code combinations on a telegraph printer. I

A further object of the invention is to provide a simple and effective arrangement for operating, a selector or relay in response to transmitted code combinations having a definite time relation and to the transmission of such cod combinations in succession, one after the other,

without other code combinations being interposed.

A still further object of the invention is to provide a system of the character described in which the selector is operated by two successive characters or code combinations of impulses irrespective of the period of time elapsing between the transmission of the successive code combinations, providing no other code combination is transmitted during said period.

Other objects and advantages of the invention will appear from the following description of the embodiments thereof shown in the accompanying drawing, wherein:

Fig. 1 is a diagrammatic view of a preferred form of switching selector responsive to a plurality of predetermined code combinations irrespective of the time elapsing between the transmission of the respective code combinations;

Fig. 2 is a similar view of a modification in which the controlling impulses must be transmitted with a definit time relation.

Referring to the drawing, Fig. 1 illustrates a portion of the mechanism of a printer similar tojthat shown in the patent to Noxon et al.,

No. 2,205,430 granted June 25, 1940. If desired, other forms of printers may be employed in carrying out the invention. The printer employs the usual printer selector magnets l0 and connected in series relation in the line circuit and arranged to control the operation of the printer in response to code combinations of impulses received over the line circuit.

The detailed construction of the complete printer is shown in the above mentioned patent to Noxon et al. and only that portion of the printerpmechanism involved in the presentinventionis illustrated in the accompanying drawing. As shown, the operating mechanism includes an operating shaft |5 on which is mounted an operating cam l5 and an auxiliary cam ll, the said cams being arranged to make one revolution from their positions shown for each cycle of operation of the printer. The mechanism further comprises an operating bail l8 which is pivoted on the axis reprsented by theshaft or'rod l9 and swings downwardly during each printing cycle to operate a selected type or function bar (not shown) through the associated hook elements or bars such as 2|, 22, 23. The operationof the bail I8 is effected in the particular mechanism illustrated through the instrumentality of a cam follower 24 and spring 25, the cam follower 24 engaging the cam member I6 on the operating shaft. It will be understood that one of the hook elements or bars similar to those indicated at 2|, 22, 23 is selected by suitable selector mechanism (not shown) in response to the code combination impressed upon the magnets I0 and H, and. displaced laterally to a position where it will be engaged by the operatingbail l8 and depressed to actuate the associated type or function bar.

In accordance with the present invention, three of the selectively operable elements are arranged to actuate contacts 3|, 32 and 33 to control the operation of selective switch means which as shown is a relay 35. In order to obviate theaccidental or undesired operation of the relay 35 during regular transmission of messages, a plurality of code combinations for opof contacts 31 which are closed momentarily by";

the cam member I! on the operating shaft-at an the timing characteristics of the circuit of the control electrode 39.

The selective switch or relay may be employed to operate a signal, to close a control circuit, or for any other desired purpose. As shown, the upper armature and front contact of said relay are connected to the circuit of a reperforator 45, for example to' render the reperforator responsive to signals received over the line to which the printer is connected. The reperforavtor may be employed to perforate tape in accordance'with the received signals which may then intermediate point in the stroke of the-operating bail l8 so that the contacts 31 are not closed until after the closure of.contacts 3|, 32 or 33,"; if one of these contacts is selected, andopened before any of said contactsar opened by. the upward movement of the bail l8 at the end ofthe' printing cycle. space-discharge device 38.shown as a conventionahtriodf with its controlelectrode'39 normally biased to a negative potentialby its connection to negative battery through the resistance 40; Thecontrol'electrode'39 may also be fconne cte'dto ground through a resistance 4| and the contacts 31 when said contacts close. A condenser 42'is also connectedb'etween the cathode and the control electrodefto' maintain the positive-bias potential impressed on the control elecjtrodei39 throughcontacts 3| until thecontrol electrode is grounded by the contacts 3'! through thelow' resistance 4|,ithereby discharging the "condenser 42;;The resistance 40 is only for the purpose of stabilising'operation and may'beyfor example; of a value of. one or 'two megohms. When the control ele'ctrode39of the device is at fa positive potential'with respect to the cathode, the space-discharge device is "rendered conductive" until the contacts 31" are close nected through contacts 32and 33 to theoperating and release windings 43 and 44 respec- "tive1y,ofrelayf35." V V 1 The operation is as" follows: when" the shift code "combinationis' followed by character F without. any "interposed code combinations, the fcontacts 3| close,'"and contacts 31 close and open before contacts 3'freopen;" then when F is re- 'ceive'd; contact's'"32 andfitlien" contacts 31 are closed. r'r e spac'e discharge device 38 is thus Irendered conducting 'by the positive potential applied to 'the' control electrode 39 through; the cbnt'actsSI' ineh remam "closeduntil after the icontacts s yhavefopeneaw impress a positive. ph rgeupen the condenser :42, Upon the initial closhre of "the contacts fl (when the character received) before contacts 3] reclose, a circuit is closedfromgrorind through the spaceidischarg e; device; contacts 32 and the operatwinding 43 of relay 35 to battery,,. whereupon said relaybecomes energized and locks up through sai d ;twindi ng and the lower armature and front contaet of, said relay. toground; :Thus the relay 35 becomes lockedup during the second .cycle of thej printer even though .the subsequent closure of thencontacts 31 discharges the condenser; 4 2 .iand thereby rendersthespace-discharge device, 38 nonconducting by reason ofthe discharge .of-.;the condenser 42. \After the con- ;tacts.3 Lreopen,.i.negative battery is applied to .the, control electrode --39 and, condenser '42 ,;through the resistance.- r. The operation is thus dependent. upon the timing of the operation of be repeated at any time by the operation of a tape transmitter (not shown) in the usual manner.

ceipt of a ,shift combination followed by character-S with no intervening characters. In this The system further embodies a.

d. The anode, or plate of thespace-discharge device is con- --case of transmission'at the usual contacts; 31,-. 3 2. and 31;: and particularly upon case theoperation of contacts 3| in response to the shift combination renders the space-discharge device 38 conducting as described above. 'If the contacts 33. are then closed upon the next printingcycle" in-response'to the receipt of the characters, a circuit isclosed from positive battery through the middle armature and front contact of relay 35, the neutralizing or releasing winding'fl of relay 35; contacts 33and the spacedischargedevice 38, whereupon the relay 35 is restored to normal. It will be evident that if "any other code combination had been received between the shift combination and the character F or between the fshift combinationand the character s, the closure-of contacts 31- by the 0am I! would render; the space-discharge device 38 -nonconductingfahd'the subsequent transmission of the characters' l and S will have noeflect. However, the second characters of the selector codes need-not be sentimniediately following the first character -or fshift combination since the .positive charge :on' the condenser 42 *will remain -for. a n appreciable time andthe space-discharge device 38-. remain's cohducting until said'charge is partly or completely dissipated. This is advantageousin systems where the selector code combination may' be-sent manually as from a keyboard and thus income-cases there may be :2 pause betweenj thetwo selector code combina- 10118." i F? Fig. .2 illustrates afmodification of the invention. in which sets of contacts 3|a, 32a, 33a, corresponding to thecontacts 3|, 32 and 33 of 1 are employedto control; the energization or release of a relay 35a when two predetermined code combinations are received within a definite period of time,'for example of the order'of that *requiredfor the transmission of two or three characters. In =thiscase it will be assumed that the contacts 3|a are o'perated upon the receipt of the shift?-codecombination; and the contacts 32a .upon receipt of the unshift code combination-, :and the contactS 3311 upon the receipt of the period 'do't code combination; One switching function is effected upon receipt of a ffshift code combination followed immediately by an .unshift code combination,- andanother function uponvth'e receipt of a double period dot code combination; The second code combination of each pair must be transmitted within a predetermined period after the first combination," for example not more than 300 milliseconds in-the r rate 01;" about 51K characters 'per' s'ec'ond' The period allowed *for the transmission' of the second codeycomtbination mayibe fvar ied softhat the:selector"is adapted to function at ianydesired transmitting rate. Thus the figures mentioned are simply typical of the conventional printing telegraph system as operated in practice. Any other code combinations may also be used to control the selector but preferably the sequence of combinations employed are those which do not ordinarily occur in message transmission.

As shown in Fig. 2, the control contacts 310., 32a ar connected to the space-discharge device 50, having its cathode-anode circuit in series relation with the operating winding 43a of the relay 35a. The contacts 33a are arranged to energize the release winding 44a of the relay 35a through a second space-discharge device The control electrodes 52 and 53 of the respective space-discharge devices 50 and 5| are connected to ground through leak resistances 54 each shunted by a condenser 55. The values of the resistances 54 and condensers 55 are selected to give the desired timing characteristics to the control electrode circuit of each space-discharge device, for example to maintain the potentialof said control electrode at such a point that the space-discharge device remains conducting for a period of 300 milliseconds. Both of the control electrodes 52 and 53 are normally at ground potential. When the control contacts 3la close upon receipt of a shift code combination, the potential of the control electrode 52 is made more positive with respect to the cathode since the contacts 3la connect the control electrode 52 to a positive point on the circuit including the heater for the cathode of the space-discharge device 50 in series with the heater of the second space-discharge device 5|, the resistance 51 and positive battery. Thus, since the cathode of each of the devices 50 and 5| is normally at a positive potential with respect to ground, the control electrodes of said devices are at a negative relative potential when they are grounded. The positive charge impressed upon the condenser 55 associated with the space-discharge device 50 when the contacts 3la are closed renders the device 50 conducting for the period, for example 300 milliseconds, determined by the time characteristics of the control electrode circuit. If the unshift code combination is received immediately following the shift code combination, the contacts 32a are closed while the space-discharge device 50 is still conductive and the energizing winding 43a of the relay 35a will be energized through said space-discharge device 50. If, however, one or more characters are interposed between the shift and unshift code combinations, the space-discharge device 50 will be nonconductive when the contacts 32a close, and the selector relay will not be operated.

The relay 35a is released upon the receipt of two period dot code combinations sent one immediately following the other. The first code combination operates contacts 33a and connects positive battery momentarily through the lower make contacts 33a to the condenser 58. Upon the restoration of the contacts 33a the positive charge on the condenser 58 is impressed upon the control electrode 53 of the space-discharge device 5|, thus rendering said device conducting for a predetermined period of time, for example 300 milliseconds. If the second period dot code combination is immediately received, the closure of the contacts 33a energizes the release coil 44a of relay 35a through upper make contacts 33a and the space-discharge device 5|. After the space-discharge device 5la becomes nonconducting, the receipt of a period dot code combination does not affect relay 35a and thus single periods may be transmitted in the regular way without releasing relay 35a.

Two modifications of the invention have been shown and described in order to illustrate the principles thereof but other modifications will occur to those skilled in the art and may be made without departing from the scope of the invention as defined in the appended claims.

We claim: r

1. A printing telegraph system comprising a printer embodying selectively operable elements or bars and means for operating the same in'response to line current impulses, contacts actuated by said elements or bars upon the receipt of predetermined code combinations of impulses, a space-discharge device operatively connected to a plurality of said contacts and provided with a control electrode, means for imparting a definite time characteristic the circuit of the control electrode, switch means and means including said contacts and spacedischarge device for operating said switch means in response to predetermined code combinations.

2. A printing telegraph system comprising a printer embodying selectively operable elements or bars and means for operating the same in response to line current impulses, contacts actuated by said elements or bars upon the receipt of predetermined code combinations of impulses, a switch, a space-discharge device provided with a control electrode, means including said contacts and the control electrode for varying the conductivity of said space-discharge device upon the receipt of a first predetermined code combination of impulses, means including said contacts and said space-discharge device for operating said switch upon receipt of a second predetermined code combination of impulses and means for preventing the operation of said switch by said second code combination if a different code combination precedes said second code combination.

3. A printing telegraph system comprising a printer embodying selectively operable elements or bars and means for operating the same in response to line current impulses, contacts actuated by said elements or bars upon the receipt of predetermined code combinations of impulses, a switch, a space-discharge device provided with a control electrode normally biased to a potential rendering said space-discharge device nonconductive, means including said contacts for varying the potential of said control electrode upon the receipt of a predetermined code combination of impulses and means for operating said switch or restoring the normal bias potential of said control electrode depending upon the next code combination of impulses received whereby said switch is operated only upon the receipt of two. successive predetermined code combinations.

4. A printing telegraph system comprising a printer embodying selectively operable elements or bars and means for operating the same in response to line current impulses, contacts actuated by said elements or bars upon the receipt of predetermined code combinations of impulses, a switch, a space-discharge device provided with a control electrode, a second set of contacts in said printer actuated concurrently with each printing cycle and connected to said control electrode of the space-discharge device, means including said first-mentioned contacts and space-discharge device for operating said switch to the current flowing in response to line-currentimpulses, contacts actuated by said elements or bars upon the; receipt of predetermined code; combinations of impulses, a switch, a space-discharge device provided with a cathode and -a control electrode, a condenser connected betweenisaid cathode and control electrode, a leakresistance in parallel relationto: said condenser, a secondcondenser, means including certain of said contacts for charging said second condenser and then transferring the charge to said first-mentioned condenser upon; receipt of ,a single predetermined -code combination of. impulses, and means including said condensers and space-discharge device foroperating said switch upon receipt of a plurality of code combinations ,within a predeterminedperiod of time.-

combination of impulses before the 6. A printing telegraph system comprising a printerembodying selectively operable elements or bars andmeans ioroperating the same in response to ,line current impulses, contacts actuated by said elements or bars upon the receipt of predetermined code combinations of impulses, a switch, a space-dischargedevice provided with acontrol electrode, means including said contacts and the control electrode for varying the conductivity-of said space-discharge device upon cthe receipt of a firstpredetermined code combinationof impu ses, means to restore the conductivity of said space-discharge device to its initial condition after a predetermined time delay and means including said contacts, and said space-discharge device'for operating said switch upon receipt of a second predetermined code conductivity of said space-dischargerdevice has been restored to its initial condition;

' RONALD v. MORGENS'I'ERN.

HENRY P. GILBERT.

CERTIFICATE OF CORRECTION. Patent No. 2,279,555. April 14, 19h2.

RONALD v. MORGENSTERN, ET AL.

It is hereby certified that error appears in the above numbered patent requiring correction as follows: In the grant, line 1, and inthe heading to the printed specification, line 14., residence of first named inventor, after "Irvington," insert -New York,--; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 9th day of June, A. D. 19142.

- Henry Van Ar'sdale, (Seal) Acting Commissioner of Patents. 

